With the four-month-old increase in American troops showing only
modest success in curbing insurgent attacks, American commanders are turning
to another strategy that they acknowledge is fraught with risk: arming
Sunni Arab groups that have promised to fight militants linked with Al
Qaeda who have been their allies in the past.

American commanders say they have successfully tested the strategy in
Anbar Province west of Baghdad and have held talks with Sunni groups in
at least four areas of central and north-central Iraq where the insurgency
has been strong. In some cases, the American commanders say, the Sunni
groups are suspected of involvement in past attacks on American troops
or of having links to such groups. Some of these groups, they say, have
been provided, usually through Iraqi military units allied with the Americans,
with arms, ammunition, cash, fuel and supplies.

American officers who have engaged in what they call outreach to the
Sunni groups say many of them have had past links to Al Qaeda in Mesopotamia
but grew disillusioned with the Islamic militants’ extremist tactics,
particularly suicide bombings that have killed thousands of Iraqi civilians.
In exchange for American backing, these officials say, the Sunni groups
have agreed to fight Al Qaeda and halt attacks on American units. Commanders
who have undertaken these negotiations say that in some cases, Sunni groups
have agreed to alert American troops to the location of roadside bombs
and other lethal booby traps.

But critics of the strategy, including some American officers, say it
could amount to the Americans’ arming both sides in a future civil
war. The United States has spent more than $15 billion in building up
Iraq’s army and police force, whose manpower of 350,000 is heavily
Shiite. With an American troop drawdown increasingly likely in the next
year, and little sign of a political accommodation between Shiite and
Sunni politicians in Baghdad, the critics say, there is a risk that any
weapons given to Sunni groups will eventually be used against Shiites.
There is also the possibility the weapons could be used against the Americans
themselves.

American field commanders met this month in Baghdad with Gen. David H.
Petraeus, the top American commander in Iraq, to discuss the conditions
Sunni groups would have to meet to win American assistance. Senior officers
who attended the meeting said that General Petraeus and the operational
commander who is the second-ranking American officer here, Lt. Gen. Raymond
T. Odierno, gave cautious approval to field commanders to negotiate with
Sunni groups in their areas.

One commander who attended the meeting said that despite the risks in
arming groups that have until now fought against the Americans, the potential
gains against Al Qaeda were too great to be missed. He said the strategy
held out the prospect of finally driving a wedge between two wings of
the Sunni insurgency that had previously worked in a devastating alliance
— die-hard loyalists of Saddam Hussein’s formerly dominant
Baath Party, and Islamic militants belonging to a constellation of groups
linked to Al Qaeda.

Even if only partly successful, the officer said, the strategy could
do as much or more to stabilize Iraq, and to speed American troops on
their way home, as the increase in troops ordered by President Bush late
last year, which has thrown nearly 30,000 additional American troops into
the war but failed so far to fulfill the aim of bringing enhanced stability
to Baghdad. An initial decline in sectarian killings in Baghdad in the
first two months of the troop buildup has reversed, with growing numbers
of bodies showing up each day in the capital. Suicide bombings have dipped
in Baghdad but increased elsewhere, as Qaeda groups, confronted with great
American troop numbers, have shifted their operations elsewhere.

The strategy of arming Sunni groups was first tested earlier this year
in Anbar Province, the desert hinterland west of Baghdad, and attacks
on American troops plunged after tribal sheiks, angered by Qaeda strikes
that killed large numbers of Sunni civilians, recruited thousands of men
to join government security forces and the tribal police. With Qaeda groups
quitting the province for Sunni havens elsewhere, Anbar has lost its long-held
reputation as the most dangerous place in Iraq for American troops.

Now, the Americans are testing the “Anbar model” across wide
areas of Sunni-dominated Iraq. The areas include parts of Baghdad, notably
the Sunni stronghold of Amiriya, a district that flanks the highway leading
to Baghdad’s international airport; the area south of the capital
in Babil province known as the Triangle of Death, site of an ambush in
which four American soldiers were killed last month and three others abducted,
one of whose bodies was found in the Euphrates; Diyala Province north
and east of Baghdad, an area of lush palm groves and orchards which has
replaced Anbar as Al Qaeda’s main sanctuary in Iraq; and Salahuddin
Province, also north of Baghdad, the home area of Saddam Hussein.

Although the American engagement with the Sunni groups has brought some
early successes against Al Qaeda, particularly in Anbar, many of the problems
that hampered earlier American efforts to reach out to insurgents remain
unchanged. American commanders say the Sunni groups they are negotiating
with show few signs of wanting to work with the Shiite-led government
of Prime Minister Nuri Kamal al-Maliki. For their part, Shiite leaders
are deeply suspicious of any American move to co-opt Sunni groups that
are wedded to a return to Sunni political dominance.

With the agreement to arm some Sunni groups, the Americans also appear
to have made a tacit recognition that earlier demands for the disarming
of Shiite militia groups are politically unachievable for now given the
refusal of powerful Shiite political parties to shed their armed wings.
In effect, the Americans seem to have concluded that as long as the Shiites
maintain their militias, Shiite leaders are in a poor position to protest
the arming of Sunni groups whose activities will be under close American
scrutiny.

But officials of Mr. Maliki’s government have placed strict limits
on the Sunni groups they are willing to countenance as allies in the fight
against Al Qaeda. One leading Shiite politician, Sheik Khalik al-Atiyah,
the deputy Parliament speaker, said in a recent interview that he would
rule out any discussion of an amnesty for Sunni Arab insurgents, even
those who commit to fighting Al Qaeda. Similarly, many American commanders
oppose rewarding Sunni Arab groups who have been responsible, even tangentially,
for any of the more than 29,000 American casualties in the war, including
more than 3,500 deaths. Equally daunting for American commanders is the
risk that Sunni groups receiving American backing could effectively double-cross
the Americans, taking weapons and turning them against American and Iraq’s
Shiite-dominated government forces.

Americans officers acknowledge that providing weapons to breakaway rebel
groups is not new in counterinsurgency warfare, and that in places where
it has been tried before, including the French colonial war in Algeria,
the British-led fight against insurgents in Malaya in the early 1950s,
and in Vietnam, the effort often backfired, with weapons given to the
rebels being turned against the forces providing them. Maj. Gen. Rick
Lynch, commander of the Third Infantry Division and leader of an American
task force fighting in a wide area between the Tigris and Euphrates rivers
immediately south of Baghdad, said at a briefing for reporters on Sunday
that no American support would be given to any Sunni group that had attacked
Americans. If the Americans negotiating with Sunni groups in his area
had “specific information” that the group or any of its members
had killed Americans, he said, “The negotiation is going to go like
this: ‘You’re under arrest, and you’re going with me.’
I’m not going to go out and negotiate with folks who have American
blood on their hands.”

One of the conditions set by the American commanders who met in Baghdad
was that any group receiving weapons must submit its fighters for biometric
tests that would include taking fingerprints and retinal scans. The American
conditions, senior officers said, also include registering the serial
numbers of all weapons, steps the Americans believe will help in tracing
fighters who use the weapons in attacks against American or Iraqi troops.
The fighters who have received American backing in the Amiriya district
of Baghdad were required to undergo the tests, the officers said.

The requirement that no support be given to insurgent groups that have
attacked Americans appeared to have been set aside or loosely enforced
in negotiations with the Sunni groups elsewhere, including Amiriya, where
American units that have supported Sunni groups fighting to oust Al Qaeda
have told reporters they believe that the Sunni groups include insurgents
who had fought the Americans. The Americans have bolstered Sunni groups
in Amiriya by empowering them to detain suspected Qaeda fighters and approving
ammunition supplies to Sunni fighters from Iraqi Army units.

In Anbar, there have been negotiations with factions from the 1920 Revolution
Brigades, a Sunni insurgent group with strong Baathist links that has
a history of attacking Americans. In Diyala, insurgents who have joined
the Iraqi Army have told reporters that they switched sides after working
for the 1920 group. And in an agreement announced by the American command
on Sunday, 130 tribal sheiks in Salahuddin met in the provincial capital,
Tikrit, to form police units that would “defend” against Al
Qaeda.

General Lynch said American commanders would face hard decisions in choosing
which groups to support. “This isn’t a black and white place,”
he said. “There are good guys and bad guys and there are groups
in between,” and separating them was a major challenge. He said
some groups that had approached the Americans had made no secret of their
enmity.

“They say, ‘We hate you because you are occupiers’
” he said, “ ‘but we hate Al Qaeda worse, and we hate
the Persians even more.’ ” Sunni militants refer to Iraq’s
Shiites as Persians, a reference to the strong links between Iraqi Shiites
and the Shiites who predominate in Iran.

An Iraqi government official who was reached by telephone on Sunday said
the government was uncomfortable with the American negotiations with the
Sunni groups because they offered no guarantee that the militias would
be loyal to anyone other than the American commander in their immediate
area. “The government’s aim is to disarm and demobilize the
militias in Iraq,” said Sadiq al-Rikabi, a political adviser to
Mr. Maliki. “And we have enough militias in Iraq that we are struggling
now to solve the problem. Why are we creating new ones?”

Despite such views, General Lynch said, the Americans believed that Sunni
groups offering to fight Al Qaeda and halt attacks on American and Iraqi
forces met a basic condition for re-establishing stability in insurgent-hit
areas: they had roots in the areas where they operated, and thus held
out the prospect of building security from the ground up. He cited areas
in Babil Province where there were “no security forces, zero, zilch,”
and added: “When you’ve got people who say, ‘I want
to protect my neighbors,’ we ought to jump like a duck on a june
bug.”